JPS6134442B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an oil-soluble additive that can be incorporated into a lubricant composition.

As newer engines are developed, the requirements for the lubricants used become increasingly strict. Conventionally, various types of additives have been added to improve the properties of lubricating oils, such as viscosity index (VI) and dispersibility. Examples of known additives added to improve the viscosity index of lubricating oils include:
Mention may be made of binary block copolymers having the general formula AB (where A is styrene and B is hydrogenated isoprene). This known block copolymer is disclosed in, for example, US Pat.
It is described in specifications such as No. 3763044 and No. 3772196. It would be very advantageous if a single additive could improve the various properties of a lubricant at the same time, and in this case the manufacturing cost of the lubricant would be greatly reduced. However, when attempting to improve more than one property of a lubricating oil, care must be taken to avoid deterioration of other properties. For example, in the invention described in U.S. Pat. No. 3,864,268, there is an oxidation reaction step for attaching a polar group to the backbone of the polymer. The stability of the lubricant was reduced due to the presence of "sites".

The present invention comprises (a) a polystyrene block having the general formula AB (where each polymer block A is a polystyrene block having an average molecular weight within the range of 25,000 to 50,000, and each block B having an average molecular weight of 35,000 to 100,000); This is a polymer block of _4-5 conjugated diene.75-98% of the aliphatic unsaturated bonds in this block copolymer have been reduced by hydrogenation, while 20% of the aromatic unsaturated bonds have been reduced. % reduced) with maleic anhydride in the presence of a solvent at a temperature of 180-250°C, and (b) the above step ( the product obtained in a) and having the following formula _NH2 ( _CH2 ) _o [NH( _CH2 ) _o ] _NH2 , where n is from 2 to 4 and m is from 0 to 6. amine and/or at least 2
This invention relates to a method for producing an ashless oil-soluble additive for lubricating oils, which has the effect of improving both dispersibility and viscosity index, which is characterized by reacting the additive with a C _2-12 alkane polyol having hydroxyl groups. .

In order to obtain a final product with good viscosity index improvement properties, it is essential that block copolymers with values within the above-mentioned range should be used. If this molecular weight is extremely low,
VI-improvement becomes very low, while if the molecular weight is extremely high, stability becomes poor due to high shear forces in the engine. moreover,
Selective hydrogenation of said polymer must be carried out to a specified value within said narrow range,
This is also very important. There are two reasons for setting such critical conditions. The first reason is that it is important to make as many aliphatic double bonds as saturated bonds as possible in order to improve the stability of the polymer under lubricating conditions. The second reason is that all aliphatic double bonds must not be reduced. This is because, in the present invention, the remaining aliphatic double bonds must be reacted with maleic anhydride. Ideally, when the optimal amount of maleic anhydride is reacted with the polymer, no extra double bonds are attached to the block polymer, so that the block polymer is free from oxidation. (2 in the block copolymer)
(If there are heavy bonds, they are susceptible to oxidation), so the selective hydrogenation is preferably carried out under strictly controlled conditions.

The block copolymers used in this invention are selectively hydrogenated binary block copolymers having the general formula AB, where each A is polystyrene and each B is a hydrogenated (before implementation, it is a polymer of C _4-5 conjugated dienes). Examples of B blocks before hydrogenation include isoprene polymer blocks and butadiene polymer blocks. When the monomer used is butadiene, approximately 35 of the fused butadiene units in the butadiene polymer block
Preferably, ~55 mol% has a 1,2-structure. For example, when such a block is hydrogenated, the resulting product is a regular copolymer block of ethylene and butene-1 (EB) or a similar block. be. When the monomer used is isoprene, it is preferred that at least about 80 mole percent of the isoprene units have a 1,4-configuration (which can be of cis or trans configuration). The resulting product is a regular copolymer block (EP) of alternating ethylene and propylene.

This block copolymer can be produced using a lithium-based initiator (preferably a lithium alkyl such as lithium butyl or lithium amyl) according to a conventional method. The polymerization can generally be carried out in solution, in which case inert solvents such as cyclohexane, alkanes (eg, butane, pentane) and mixtures thereof can be used. The first monomer to be polymerized (which can be styrene, butadiene or isoprene) is injected into the reaction system and contacted with the polymerization initiator. This polymerization initiator is
It is preferable to add the amount (calculated amount) necessary to produce a polymer having a predetermined molecular weight. After producing a product with a predetermined molecular weight and removing the remaining first monomer, a second monomer is injected into the living polymer-containing reaction system, and a block copolymerization reaction occurs, resulting in the production of living block copolymerization. Because I will,
The living block copolymer is killed by adding methanol or water. In this way, a flexible block copolymer is obtained.

The average molecular weight of each polystyrene block in the precursor block copolymer is about 25,000~
50,000 preferably about 30,000 to 45,000. The average molecular weight of the diene polymer block is approximately 35,000~
100,000 preferably about 50,000 to 80,000. The block copolymer should have a minimum molecular weight of about 60,000 and a maximum molecular weight of about 150,000. The weight ratio of A:B can generally vary within the range of about 0.5:1 to about 0.7:1.

The precursor block copolymer is selectively hydrogenated under selected conditions, whereby about 75-98% of the aliphatic unsaturation in the block copolymer, preferably about 90-95% (for example 80%) of the double bonds are saturated and no more than about 20% of the double bonds of the polystyrene block are hydrogenated. Preferably, about 90-95% of the olefinic double bonds in the conjugated diene polymer block are hydrogenated. A block copolymer having the above-mentioned degree of hydrogenation is produced, thereby:
It is important to be able to use the remaining olefinic bonds to convert the polymer into the desired derivative. This hydrogenation reaction is preferably carried out according to the following method. The precursor block copolymer is dissolved in an inert solvent (the polymerization solvent described above is generally used), a cobalt, nickel or iron carboxylate or alkoxide (reduced with an aluminum alkyl compound is used) is added, and 20 Pressurize with hydrogen to a pressure of 50-500 psig at a moderate temperature of ~70°C. This selective hydrogenation reaction proceeds to the desired extent after about 0.1 to 2 hours. For more information on this reaction,
See, for example, U.S. Pat. No. 3,595,942 to Wald et al.

The number of residual olefin bonds in the product obtained by this selective hydrogenation reaction can be determined by infrared spectroscopy, iodine value measurement or ozone titration (0.1 to
10 meq/g). Infrared spectrum analysis shows that the infrared absorbance is at wavelengths of 10.05 microns, 10.35 microns, 10.98 microns and
The iodine value preferably tapers off at 13.60 microns and is preferably a value between about 0 and 100, indicating that at least about 75% of the olefinic double bonds are saturated. It is. The iodine value shown here is a value measured by a conventional measuring method for fat analysis, and its unit is g (iodine) / 100 g (polymer).
It is. In this analytical method, iodine is not added to aromatic double bonds, and therefore only olefin double bonds can be calculated. The iodine number of the hydrogenated block copolymer depends in part on the iodine number of the precursor copolymer, that is, on the ratio of the molecular weight of the diene polymer block to the molecular weight of the polystyrene block, but it is the most useful. The iodine number of the hydrogenated block copolymer with a large iodine value (that is, the hydrogenated block copolymer) falls within the above-mentioned specified range. This concept can also be applied to titration operations using ozone.

It is undesirable to hydrogenate the polystyrene block along with the diene polymer block, and this is an expensive operation. When only the diene polymer block is hydrogenated,
The necessary saturated aliphatic polymer structure is created to ensure improved stability. On the other hand, in the case of hydrogenation of the polystyrene block, higher temperatures and pressures are required than those necessary to produce the selectively hydrogenated block copolymer described above. Furthermore, the cyclohexane-type ring produced by hydrogenation of the polystyrene unit is more easily oxidized than its precursor, a non-hydrogenated aromatic precursor. As is clear from the above description, the selectively hydrogenated block copolymers of the present invention are better lubricant additives than fully hydrogenated polymers, and are also less expensive to produce.

This hydrogenation is not completely "selective" and under the conditions mentioned some of the aromatic rings may be hydrogenated. Such a situation can occur when using a very highly active catalyst sample, which is normally a highly selective catalyst, or when using a certain specific catalyst. Therefore, 20 of the aromatic double bonds in this block copolymer
% or less may be hydrogenated. For this reason, the hydrogenated block copolymer used in the present invention contains at least 75% of the diene polymer block.
Preferably, it is 80% or more, but not more than 98% saturated, and 0 to 20% of the styrene polymer block is saturated, and this is within the scope of the present invention. should be understood.

This AB-type selectively hydrogenated block copolymer is then reacted with maleic anhydride in the presence of a solvent. This maleic anhydride reacts with the remaining olefinic unsaturated bonds in this block copolymer. Generally, about 10-100% of the remaining double bonds in the block copolymer, preferably 50-100%
95% is converted to succinic anhydride groups (succinic anhydride groups). Attempting to convert all of the double bonds in this block copolymer to the anhydride group is impractical and uneconomical, so maleated polymers are generally used. There will be some amount of unreacted double bonds in the structure of the product.

A variety of solvents can generally be used in the maleation step, including non-olefin petroleum hydrocarbons, aromatics, and halogenated hydrocarbons. The preferred solvent is a lubricating oil base stock. Another preferred solvent is trichlorobenzene. The maleation step may be conveniently carried out in the presence of the block copolymer in the solvent, preferably at a concentration of about 1 to 10% by weight.

A stoichiometric excess of maleic anhydride is generally used to react with all remaining double bonds in the diene portion of the selectively hydrogenated block copolymer. Preferably, at least 1 mol of maleic anhydride is used per olefinic unsaturated bond present in this selectively hydrogenated block copolymer, and the equivalent amount of maleic anhydride and the olefinic double bond is The ratio is about 1:1 to 2:
1 is particularly preferred. However, it is also possible to use less than stoichiometric amounts of maleic anhydride.

This maleation reaction is carried out using a radical reaction initiator such as a tertiary hydroperoxide.
can be carried out with or without the use of an initiator) or a catalyst. A temperature of about 180 DEG to 250 DEG C. is generally maintained for about 1 to 10 hours while carrying out this thermal reaction. For example, the reaction can be carried out at about 225°C for about 4 hours. Excess maleic anhydride can generally be removed by vacuum distillation or by the use of a stripping gas stream.

According to a preferred embodiment, this maleation reaction is carried out in the presence of chlorine. The chlorination reaction for isoptene polymers is disclosed in British Patent No. 949981. It is preferable to determine the amount of chlorine used (mole ratio) so that 0.3 to 1.5 moles of chlorine come into contact with the mixture of the copolymer and maleic anhydride, and 0.5 to 1.2 moles of chlorine are used per 1 mole of maleic acid. is more preferable. As far as the conversion reaction of the copolymer is concerned, there appears to be no lower limit to the amount of chlorine that can be used. However, in practice, it is preferable to use the amount within the above range.

Advantageously, the mixture of copolymer and maleic anhydride is heated to reaction temperature before contacting it with chlorine. The mixture is contacted with a submolar amount of chlorine before a substantial amount (eg, less than half the amount) of maleic anhydride has reacted. For example, it is advantageous to contact the chlorine as described above when the maleic anhydride has not yet substantially reacted. The rate of introduction of chlorine into this mixture can vary within a very wide range, but is preferably the same as the rate of reaction of chlorine (the amount of chlorine absorbed into the mixture, ie the rate of absorption). Generally, chlorine can be introduced over a period of 0.5 to 10 hours, preferably 3 to 7 hours.

After the chlorination treatment, it is advantageous to subject the reaction product mixture to a post-reaction treatment, for example a heat treatment. This heat treatment is advantageously carried out at a temperature of 140-220°C, preferably 160-210°C. It is generally preferred, however, that the heat treatment is carried out under conditions such that no reaction mixture is removed during the heat treatment, for example under reflux conditions. This heat treatment lasts from 0.1 to 20 hours, preferably
Can be carried out for 0.5 to 10 hours. If the process is carried out for a longer period of time, the amount of tar-like by-products produced tends to increase.

The maleated polymer is then reacted with an amine and/or an alkane polyol to form an oil-soluble product according to the invention.

The amine used here is a polyamine having the formula:

NH ₂ (CH ₂ ) _o [NH (CH ₂ ) _o ] NH ₂ In the above formula, n is 2 to 4 and m is 0 to 6
It is. Examples of such polyamines include tetraethylenepentamine, tripropylenetetramine,
N-aminoalkylpiperazine such as N-(2
-aminoethyl)-piperazine, N,N'-di-
Examples include (2-aminoethyl)-piperazine. Preferred are tetraethylenepentamine,
and the corresponding commercial mixtures such as "Polyamine-H" and "Polyamine-500".

Alkane polyols that can be advantageously used to produce the desired ester products are _C2 - _C12 alkane polyols having at least 2 (preferably at least 4) hydroxyl groups, examples of which include: Mentioned: trihydroxyalkanes such as trihydroxybutane, -pentane, -hexane, -heptane, -octane, -nonane, -dodecane, etc.; tetrahydroxyalkanes, pentahydroxyalkanes, hexahydroxyalkanes; sugar alcohols such as erythritol, pentaerythritol , tetritol, pentitol, hexitol, mannitol,
Sorbitol, glucose, etc. More preferred alcohols are pentaerythritol and mannitol. Particularly preferred is pentaerythritol.

The molar ratio of said amine or polyol to maleic anhydride is generally from 0.1:1 to 2:1, preferably from 0.5:1 to 2:1, most preferably about 1:1. The reaction conditions for this amidation or esterification reaction are generally as follows: reaction at about 150 to 250°C for about 1 to 20 hours, for example 5 hours, e.g.
The reaction is carried out at 100°C for about 1 hour, and then at 190°C for 1 hour (when carrying out the amidation reaction).

In this amidation, esterification and maleation step, it is highly preferred to carry out the reaction in the absence of oxygen. A nitrogen blanket is often used for this purpose.
The reason for carrying out the reaction in the absence of oxygen is that if oxygen is present during the preparation of the additive product, a less oxidatively stable additive product is obtained.

If an excess of amine or polyol is used, it is advantageous to remove the excess after the reaction. For this purpose, the following operations can be performed:
First, add a volume of heptane equal to the volume of dissolved additive product. An equal volume of methanol is then added. This results in two mutually separate layers, the lower layer (bottom layer) containing primarily methanol and unreacted polyamine, and the upper layer (top layer) containing primarily heptane, the solvent and Contains additive products. After separating the lower layer, the volatile substances present in the upper layer can be removed by a distillation operation. Alternatively, excess polyol can be removed under vacuum or using a stripping gas stream.

The reaction products according to the invention (i.e. the additives according to the invention) are present in lubricating oil compositions (e.g. automotive crankcase oils) at a concentration of about 0.1 to 15% by weight, preferably about 0.1 to 3% by weight. (based on the total amount of the composition). Examples of lubricating oils to which the additive according to the invention can be added include mineral oil-based lubricating oils (which may be hydrotreated) and synthetic oils. Synthetic hydrocarbon lubricating oils and non-hydrocarbon synthetic oils may also be used, examples of which include: esters of dibasic acids such as di-2-ethylhexyl sebacate, carbonate esters, phosphate esters. , halogenated hydrocarbons, polysilicone, polyglycols, glycol esters such as C ₁₃ -oxoacid diester of tetraethylene glycol. When used in gasoline or fuel oils (e.g. diesel fuel), this reaction product (i.e. the additive according to the invention) generally has a concentration of about 0.001
~0.5% by weight (based on the total fuel composition) will be used. For ease of handling, it contains a small amount of the reaction product, for example 10-45% by weight,
Large amount of hydrocarbon diluent, e.g. 95-55% by weight
You may also create and use a “concentrate” that contains the substance. This concentrate may or may not contain other additives.

Other penetrating additives may be present in the composition or concentrate, examples of which include: dyes, pour point depressants, anti-wear agents such as tricresyl phosphate. , 3 to 3 carbon atoms
Zinc sialkyl dithiophosphate having 8;
Antioxidants such as phenyl-α-naphthylamine, tertiary octylphenol sulfide, bisphenols [e.g. 4,4'-methylene-bis-
(3,6-di-tert-butylphenol)]; Viscosity index improver such as ethylene-higher olefin copolymer, polymethyl acrylate, polyisobutylene, alkyl fumarate-vinyl acetate copolymer; Other ashless dispersants or detergents agents such as overbased sulfonates
sulphonates).

Example 1 A styrene block with M _w = approx. 35000 and M _w = approx.
5 g of a block copolymer having 65,000 partially hydrogenated isoprene blocks and 0.4 meq/g of unsaturated bonds (determined by ozonometry) were dissolved in 100 g of light mineral oil. The rubber solution (i.e., block copolymer solution) was then treated with maleic anhydride at 220 DEG C. under nitrogen for 4 hours. Excess maleic anhydride was removed by nitrogen stripping.

Amidation was carried out by treatment with 0.8 g of tetraethylenepentamine at 160° C. for 2 hours. The functionalized rubber was recovered by precipitation by diluting the oil solution with isopropyl alcohol.

A spot dispersity test (SDT) was conducted according to the following method. A light mineral oil solution (concentration of 2% by weight) of the above product was mixed with the oil used in the Sequency VC engine test in a mixing ratio of 1:2. After heating the mixture to 150° C. for 16 hours, a few drops of it were placed on laboratory paper and after 24 hours the ratio of the diameter of the sludge to the diameter of the oil spot was measured. This test was to evaluate the ability of a given concentration of dispersant to promote the movement (dispersion) of suspended sludge on paper. The SDT result was 61%, which was comparable to test values of about 60-70% for commercially available dispersants.

Furthermore, a bench oxidation stability test was conducted according to the following method. While bubbling air into a light mineral oil solution (concentration: 1% by weight) of the reaction product.
Heated to 150°C for 150 hours. At the end of this test, no sludge precipitation was observed and only a small amount of pentane-insoluble material was present, less than 1% by weight. On the other hand, control samples containing commercially available polyolefin-based dispersion and VI improvers produced more sludge and the amount of pentane insoluble material present was 1.5-3.0% by weight.

Example 2 10 g of the partially hydrogenated block copolymer of Example 1 were dissolved in 1,2,4-trichlorobenzene and chlorinated with 320 mg of chlorine at 50 DEG C. for 1 hour. Maleic anhydride 0.94g
(8.2 mmol) and this solution in nitrogen
Heated to 180°C for 2 hours. Pentaerythritol
1.1 g (8.1 mmol) was added and the solution was heated to 210° C. for 6 hours under nitrogen.

After completion of this functionalization operation, the solvent was distilled off in vacuo and an equal weight of lubricating oil base stock was added. The same amount of heptane as the oil was then added and the solution was washed with methanol. Finally, volatiles were removed by stripping with nitrogen.

The product thus obtained was confirmed to have the ability to form a stable emulsion consisting of methanol and heptane (methanol and heptane are generally mutually immiscible solvents). As is clear from this experiment, this product has sufficient efficacy as a dispersant.

Further, this product was added to a commonly used lubricating oil formulation to prepare a solution with a concentration of 1% by weight (the solute was the product; the solvent was the lubricating oil formulation), and its viscosity was measured.

The viscosity at 100〓 and 210〓 is 66.9 respectively.
centistokes and 11.8 centistokes (VI=146). As is clear from the results, this product also has sufficient efficacy as a VI improving agent.

Claims (1)

[Scope of Claims] 1 (a) General formula AB (where each polymer block A is a polystyrene block having an average molecular weight within the range of 25,000 to 50,000, and each block B has an average molecular weight of 35,000 to 100,000 It is a polymer block of _{C4-5 conjugated} diene having So that 20%
(b) reacting the selectively hydrogenated block copolymer with maleic anhydride in the presence of a solvent at a temperature of 180-250°C; ) and an amine having the formula _NH2 ( _CH2 ) _o [NH( _CH2 ) _o ] _NH2 , where n is 2 to 4 and m is 0 to 6. and/or at least 2
A method for producing an ashless oil-soluble additive for lubricating oils having an effect of improving both dispersibility and viscosity index, the method comprising reacting the additive with a C _2-12 alkane polyol having hydroxyl groups. 2. Reacting the block copolymer and maleic anhydride in the presence of a solvent, and then converting the reaction into
The molar ratio of maleic anhydride to residual olefin type double bonds in the selectively hydrogenated block copolymer is within the range of about 1:1 to 2:1. A method for producing an additive according to claim 1. 3. The block copolymer and the maleic anhydride are reacted in the presence of a solvent and chlorine, and the reaction is carried out at a molar ratio of chlorine to maleic anhydride of 0.3:1 to 1.5:1. A method for producing an additive according to claim 1 or 2, characterized in that the additive is produced at a value within a range. 4. The method for producing an additive according to any one of claims 1 to 3, wherein the diene is isoprene. 5. The method for producing an additive according to any one of claims 1 to 4, wherein the amine is tetraethylenepentamine. 6. Claim 1, wherein the alkane polyol is pentaerythritol.
4. A method for producing the additive according to any one of items 4 to 4. 7. The addition according to any one of claims 1 to 6, wherein 90 to 95% of the aliphatic unsaturated bonds in the block copolymer are reduced by hydrogenation. method for producing the agent.